1. Department of Infectious Diseases, Bern University Hospital, University of Bern,
2. Division of Gastroenterology and Hepatology, and
3. Institute of Microbiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne,
4. Institute for Infectious Diseases, Faculty of Medicine, University of Bern,
5. Division of Infectious Diseases, University Hospital Lausanne, University of Lausanne,
6. Division of Infectious Diseases and Hospital Epidemiology, and
7. Institute of Medical Virology, University of Zurich,
8. Department of Infectious Diseases & Hospital Hygiene, University Hospital Basel,
9. Division of Infectious Diseases, Regional Hospital Lugano,
10. Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital St. Gallen,
11. Division of Infectious Diseases, University Hospital Geneva, University of Geneva, and
12. Institute of Social and Preventive Medicine, University of Bern, Switzerland